The Sims Bustin' Out Tips

Roommate Isolation
First of all, turn off free will. Second of all, you go outside and call that roommate out. Get in the house and go to Buy/Build mode. Build a house around your roommate. Add the doors and windows for they are necessary. Then go buy all the useful, and expensive, items you can. Make everything the same as the ones you have so that you don't have to rely on your roommate's items, or vise versa. Oh and one more thing, build a fence to isolate your roommate from you. Now you two have your own houses to live in.